1. Field of the Invention
The present invention relates to a process for producing a blade or vane ring for a gas turbine, in particular for an aero engine, and also to a corresponding blade or vane ring segment.
2. Discussion of Background Information
DE 10 2009 013 819 A1 discloses a process for producing a guide blade or vane ring, in which blade or vane blanks are produced, for example, by forging in order to then be welded together to form a guide blade or vane segment. This is intended to achieve a cost-effective process for producing a guide blade or vane ring, and instances of offsetting of adjacent blades or vanes with respect to one another are to be avoided, in order to achieve an optimization in terms of fluid mechanics.
However, DE 10 2009 013 819 A1 does not describe that the proposed process could also be used to produce rotor blades or rotor blade or vane ring segments which are exposed to strong centrifugal forces owing to the rotary movement.
In this respect in particular, however, in the case of rapidly rotating components of a gas turbine and in particular of an aero engine, there is the need to combine a suitable material selection with a necessary design of the components and an efficient and suitable production process. Thus, for example, for rapidly rotating low-pressure turbine blades or vanes, it is advantageous to produce the latter from a TiAl material, since the TiAl materials have a low specific weight and at the same time the required mechanical strength values and also sufficient resistance to the atmosphere prevailing in the working environment. However, the TiAl blades or vanes used here have to be produced by forging, in order to establish a material microstructure which satisfies the strength requirements by the suitable forging processes. At the same time, however, it is advantageous to use blade or vane ring segments, for example what are known as blade or vane twins, i.e. blade or vane ring segments having two main blade or vane parts, which have a common blade or vane root. As a result, optimization in terms of structural mechanics is possible, making it possible to efficiently connect the blades or vanes to a rotating disk of a gas turbine and ensuring an optimum load transfer.
However, the forging processes required for the properties of a TiAl blade or vane are difficult to carry out for large components, such as blade or vane ring segments, if a specific microstructure setting is required. Accordingly, it is difficult to make a production of TiAl blades or vanes by forging compatible with a combination of the blades or vanes to form blade or vane ring segments.
It is therefore desirable to have available a TiAl blade or vane ring segment, in particular for rotor blades of a gas turbine and in particular of an aero engine, in the case of which both the advantageous properties of the TiAl material with a low weight and also the required setting of the strength values by suitable forging processes can be combined with a cost-effective production. A corresponding process should therefore be easily feasible as a whole and provide reliable and reproducible results in the form of blade or vane ring segments, in particular rotor blade or vane ring segments, which can be subjected to high levels of loading and have a low weight.